Web-based courses have reached a great level of acceptance in all the areas of education. In this sense, many web platforms for online courses offer resources as complement to the theory sessions. In Science, Technology, Engineering and Mathematics (STEM) areas, the online resources may include online Laboratories. These labs are commonly a must have in the learning process. The usage of labs in automatic control education is a key element, and it gains more importance in the distance education paradigm due to the difficulties involved. However, creating and maintaining labs is not an easy task, and the online labs design comprises many steps which are time-consuming. On this subject, the whole process may be easier when using the right design tools and architectures. This works shows an implementation inside the tool Easy Java JavaScript Simulations and an use example with the coupled electric drives laboratory.

Virtual and remote labs have been around for almost twenty years and while they have been constantly gaining popularity since their appearance, there are still many people in the control education community who either do not know many details about them or do not know them at all. What are their benefits? Which examples of virtual and remote labs for control education can be found in the Internet and how spread and popular are they? What are the current trends and issues in the implementation and deployment of these tools? And the future ones? These and others are some of the questions we answer in this paper, trying to bring the attention of the control education community to these tools which, we believe, are meant to have an increasing importance and relevance for the 21st century students.

In this work, implementation issues related to multivariable Generalized Predictive Control (GPC) for processes with multiple time delays are analyzed. Due to specific properties of those processes, the resulting control system has to account for the existing delays between control variables changes and their effect on controlled outputs. In the case of Model Predictive Control (MPC) techniques, such as GPC, the dead-time issue can be captured in the process model and thus considered in the predictive mechanism of the controller. However, this working principle results in augmented matrix dimensions that considers input-output time delays as additional zero entries. This fact increases the computational load and has to be accounted for in the control system design, specially in systems where computing resources are scarce (eg. embedded systems). The reduction of the matrix dimension, and hence the computation required, depends on how the delay terms are structured. The presented analysis considers two different GPC implementations for multivariable dead-time processes, which are used to compensate for internal matrix dimensions for the multiple time delays. Each implementation mode is evaluated for two industrial multivariable processes, providing several performance indexes. Performed simulations show that the required computational load can be reduced when adequate implementation mode is selected.

The design of event-based controllers for systems with unknown states is investigated in this paper. The case of general quadratic triggering conditions that depend on the estimated state given by a Luenberger observer is studied. Novel frameworks are proposed for continuous and periodic event-based control providing criteria for asymptotic stability with the form of Linear Matrix Inequalities (LMIs). The frameworks are tested in simulation through a challenging system, such as the double rotary inverted pendulum.

In this work, a practical evaluation of the filtering method for weighing system is provided. The analyzed system form a part of the horticultural fruits sorting machine, which requires a fast and reliable weight measurements. Dynamic weighing of moving objects requires fast and adaptive signal processing techniques in order to guaranty a timely response. Thus, applied signal filtration technique must ensure that the constant component remains free of noise, transient responses of load cell as well as mechanical vibrations. In this paper fast nonstationary filtering method is applied, providing optimal tradeoff between response time and settling time of steady state value. The implementation method uses the distributed approach, where an intelligent sensor captures raw signal and applies adaptive filter. Subsequently, obtained value is transmitted to central unit, that applies weight compensation function to improve the measurement accuracy. All presented results use the real signal acquired in industrial conditions from the tests of sorting machine prototype. The analyzed approach obtains promising results for all sorting modes. Moreover, classical filtering approach is used for comparison purposes and performance evaluation.

A new 3D positioning algorithm for low cost robots is proposed. The algorithm is based on a Finite State Machine to estimate the position and orientation of the robot. The system sets dynamically the parameters of the algorithm and makes it independent of the noise in the sensors. The algorithm has been tested for differential wheel drive robots, however it can be used with different types of robots in a simple way. To improve the accuracy of the system, a new reference system based on the accelerometer of the robot is presented which reduces the accumulative error that the odometry produces.

Web-based labs are key tools for distance education that help to illustrate scientific phenomena, which require costly or difficult-to-assemble equipment. Easy Java Simulations (EJS) is an authoring tool that speeds up the creation of these kind of labs. An excellent proof of the EJS potential is the open source physics (OSP) repository, which hosts hundreds of free EJS labs. Learning management systems, such as Moodle, provide social contexts where students interact with each other. The work described in this paper looks for the synergy of both tools, EJS and Moodle, by supporting the deployment of EJS labs into Moodle and thus enriching them with social features (e.g., chat, forums, and videoconference). To test this approach, the authors have created the ball and beam lab, which helps students of automatic control engineering to train different advanced techniques (robust, fuzzy, and reset control), and compare their performance in relation to a conventional proportional-integral-derivative control.

In this work a virtual and remote lab developed to explore the properties of event-based PID controllers in a flexible link system is presented. The architecture is based on the decomposition of the system in three tiers or layers: the server, the client, and a middleware. The server layer is directly connected to the plant, the client side implements the controller and the graphical interface, and the middle-tier acts as interface between client and server. The implementation of the remote lab allows the control of a flexible link plant through a generic network. The platform is used to evaluate, with a particular case, the effectiveness of an algorithm that allows the user to find numerically the limit cycles in control schemes where the feedback is done through a level crossing sampling, and which can be applied to LTI systems with delay.

This work presents the application of Lagrange interpolation method for a signal reconstruction in event-based Generalized Predictive Control (GPC). The event-based control system is governed by level crossing sampling techniques, which monitors the controlled variable. The Lagrange interpolation method is used to reconstruct signal values between two consecutive events. The interpolated signal values are used to unify the obtained values to a base signal, which is resampled with fixed frequency. The developed event-based GPC with Lagrange interpolation is verified through a simulation study, considering several process models commonly used in industrial applications. The obtained results show a proper operation of the event-based controllers, due to good interpolation accuracy.

Web Laboratories (WebLabs) are essential resources for engineering education. Within this type of laboratory, a new Sharable Content Object Reference Model (SCORM) package design model is shown in this work. The proposed model is based on a set of resources that form a complete educational structure; taking into account the sequencing and navigation among the elements that compose it. In addition, it can be uploaded to a Learning Management System (LMS), offering to the students an effective tool to work with web labs. The package is structured in 4 sections or pages: Introduction, Theory, Virtual/Remote Laboratory (VRL) and Assessment; where the last performs an automated verification of the work done by the learner. In this way, one of the advantage of this methodology is that the instant results of the assessments, performed by the SCORM package, is stored in the inner LMS. Some WebLabs performing this methodology are being developed in the University of Jaén. In this work, an example is developed: "Modelling of Dynamic System: DC Motor". This WebLab is used in the Industrial Automation course that is included in several Industrial Engineering degrees.

Using Internet-based networking technologies traditional control laboratories in engineering education can be replaced with a remote or simulated experimental session. Thus, the way of studying becomes more flexible: the assistance to the laboratories is minimized. Accessing to the application students can make experiments and obtain results with a real plant from different localizations far from the university. This paper presents a complete virtual and remote control laboratory for experimentation of an oscillatory system: the ball and hoop. Using this application students can understand in a practical way important topics such as non-minimum phase behaviors, zeros transmission of the system, resonance, or to demonstrate control of oscillatory systems. The client-side of the virtual laboratory has been developed using the programming support provided by easy Java simulations (Ejs). The server-side has been developed using Labview and a data acquisition card.

Event-based systems are becoming increasingly commonplace, particularly for distributed real-time sensing and control. Furthermore, remote monitoring and control through data-communication networks are very popular for process supervision and control. The usage of networks provide many well-known benefits, but it also presents some limitations in the amount of transmitted data. This fact is especially visible in Wireless Sensor Network (WSN), where the bandwidth of communication channel is limited and typically all nodes are battery powered. Event-based sampling techniques appear as a some possible solution to face this problem allowing considerably saving network resources and reducing the power consumption. On the other hand, the control system performance is highly affected due to the event-based sampling techniques, being necessary to analyze and study a compromise between control quality and reduction in the control signal commutations. This paper presents all these ideas applied to the greenhouse climate control problem.

Traditionally, greenhouse installations have required a great effort to connect and distribute all the sensors and data acquisition systems. These installations need many data and power wires to be distributed along the green-houses making the system complex and expensive. For this reason, and others such as unavailability of distributed actuators, only individual sensors are usually located in a fixed point of the greenhouse selected as representative of greenhouse dynamics. On the other hand, the actuation system in greenhouses are usually composed by mechanical devices controlled using relays, being desirable to reduce the number of commutations of the control signal from security and economical point of views. The greenhouse climate control can be represented as an event-based system, where low-frequency dynamics variables have to be controlled and this control usually acts against events governed by external disturbances. Therefore, this work presents preliminary ideas and results of wireless sensor network and event-based control applied to the greenhouse climate control problem.

The standard DP (dynamic programming) algorithms are limited by the substantial computational demands they put on contemporary serial computers. In this work, the theory behind the solution to serial monadic dynamic programming problems highlights the theory and application of parallel dynamic programming on a general-purpose architecture (cluster or network of workstations). A simple and well-known technique, message passing, is considered. Several parallel serial monadic DP algorithms are proposed, based on the parallelization in the state variables and the parallelization in the decision variables. Algorithms with no interpolation are also proposed. It is demonstrated how constraints introduce load unbalance which affect scalability and how this problem is inherent to DP.

One approach to instruction based on a "learner-centered" view of learning is to provide rich environments in which learners can actually build their own knowledge. Therefore only educational software, carefully designed, can improve the efficiency of courseware. Within this framework, the World Wide Web provides a unique support for course material. Using a generalized hypermedia instructional design methodology, we integrated a hypermedia instructional module with simulation additional tools into an academic information system. This academic information system is a computer-supported environment in which collaborative discourse is the primary medium for knowledge advancement in the area of power electronics. It can be explored by learners in that they have both contextual access to knowledge displayed in a hypertext format and access to real experiences by means of simulation. In this article, we present an object-orientated approach that integrates the complete graphic user interface development.

Recently, an algorithm has been developed for synthesizing generalized parallel counters (GPC's) with a network of smaller ones [11]. In this correspondence we obtain an upper bound q, for the number of levels q in the synthesis of GPC's. This upper bound generalizes and improves the values deduced by other authors in [13] and [14].

Synthesis of generalized equal column parallel counters from smaller ones is presented. The notation used for a general counter is (n × N; d), where n is the number of input columns, N is the number of input bits in each column, and d = s · n (s = 2, 3,···) is the number of bits in the output word.